Bicycle wheel rim

ABSTRACT

A bicycle wheel rim having a circular base portion including a proximal surface and a distal surface, and a pair of integral sidewalls extending generally radially outward from an intersection region of the proximal surface and the distal surface. The distal surface of the rim has a central hump, a trough contiguous with the central hump extending axially outward from the hump, and a flat shelf immediately adjacent, contiguous with, and extending axially outward from the trough. Another embodiment of the invention is directed to a bicycle wheel including the embodied rim, a plurality a spokes engaged at respective ends thereof with the rim and a hub engaged with the plurality of spoke members at opposite ends thereof. Another embodiment of the invention is directed to a bicycle wheel assembly comprising the embodied wheel and a tube and/or tire mounted on the rim.

This application is a continuation of U.S. application Ser. No.12/197,901, filed Aug. 25, 2008, abandoned, which is a continuation ofU.S. application Ser. No. 11/965,153, filed Dec. 27, 2007, abandoned,which is a continuation of U.S. application Ser. No. 10/959,743, filedOct. 6, 2004, now U.S. Pat. No. 7,334,846, the entireties of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the invention are directed to the field of bicycle wheelrims and, more particularly, to a lighter, stronger and otherwiseimproved rim for tires with or without tubes.

2. Description of Related Art

The rim is the outer, usually metal, hoop of a bicycle wheel. The spokesof a bicycle wheel extend between a central hub of the wheel and therim. An inflatable tube and/or tire are positioned around the exteriorof the rim and air is introduced through a valve mechanism to inflatethe tube and/or tire on the rim as a functional part of a bicycle.

A prior art rim including a mounted, inflated tire is shown in crosssection in FIG. 1 to illustrate conventional rim construction. The rim100 has a base portion 101, which holds the distal portion of a spokeassembly 102. The base portion extends upward in the form of a Y to apoint 103. A mounting surface 104 of the rim has a generally concaveprofile and extends between, and connects to, opposing points 103.Sidewalls 105 extend outwards from points 103 and terminate in bead lockregion 106. Tire 110 has tire bead regions 112. In an uninflated state,the tire bead regions 112 loosely rest on rim surface 104 in the regionbetween sidewalls 105. Upon inflation, the bead portions ride up thesurface 104 until they sealingly engage sidewalls 105. Due to theconstruction of the tire bead 112, the bead lock regions 106 help tostabilize the engagement of the tire with the rim. Many variations ofrim designs are known to those skilled in the art. However, the greatmajority of rims will have the basic portions illustrated in FIG. 1.

The dimensions of various portions of a bicycle rim can significantlyinfluence rim function. For example, weight is a significantconsideration in a racing or touring rim. In addition to materialconsiderations, rim parameters such as the inside distance between therim sidewalls will largely determine useable tire size, the ability touse an inner tube within the tire, rim strength, the effect of forces onthe rim during various maneuvers such as turning, braking, etc., andothers. The shape of the surface 104 may significantly influence theease of tube/tire mounting and tube/tire inflation. The height, shapeand thickness of the rim sidewalls will contribute to overall rimweight, strength, tire stability, air leakage, and other considerationsappreciated by those skilled in the art.

Several issues can be identified with respect to conventional rimconstruction and dimensions. Rim sidewalls typically have a heightdimension, shown as H in FIG. 1, between about 0.225 inch to ≧0.265 inchfor a conventional bicycle rim. As the dimension H increases, so doesthe mechanical leverage of the tire on the rim. The greater leverageresulting from a higher sidewall further increases the forces acting inthe region of point 103 of the rim shown in FIG. 1, thus requiringadditional support at points 103 in the form of more material andincreased rim weight. A higher sidewall dimension, H, promotes greaterflexing of the rim and may result in cracking or stress fracture of therim material. In addition, as rim sidewall height, H, increases,available tire inflation volume decreases while inflation pressureincreases. Moreover, less tire surface is available resulting indecreased traction and other disadvantages. Another consequence of highsidewalls and various bead lock sizes and shapes is the well known“pinch flat” or “snake bite” that may be caused when the tube or tiregets pinched between the rim and a hard, sharp object such as a rock,curb stone or the edge of a pothole, for example. An under-inflated tirealso contributes to a pinch flat occurrence. A too soft, or too narrow(for the rim) tire more easily lets the tire bottom out when striking anobstruction resulting in the pinch holes from the bead locks or distalportion of the sidewall.

Several issues to be considered with respect to rim surface 104 as shownin FIG. 1 include rim strength, the ability to uniformly position thetire bead region on the rim prior to inflation and the ease of tireinflation, particularly with a manual pump, the interchangeable use oftubes and/or tubeless tires, and others recognized in the art. In lightof the known shortcomings of conventional bicycle rim designs, such asthose set forth above and others known to those skilled in the art, theinventor has recognized a need for an improved rim that addresses thesedisadvantages and additionally results in a lighter, stronger, moreversatile, better performing and cost effective rim for the rider.

SUMMARY OF THE INVENTION

An embodiment of the invention is directed to a bicycle wheel rim. Therim is intended to have an inner tube and/or a tire mounted onto therim. The rim has a circular base portion consisting of a proximalsurface (i.e., the surface facing the wheel hub, which as part of awheel assembly engages a plurality of spoke members, the other ends ofwhich are attached to the hub of the wheel assembly), and a distalsurface (i.e., the radially outwardly facing surface with respect to thehub), which is the surface that engages the inner tube or the bead of atire prior to inflation. The distal surface of the rim has a centralhump, a trough contiguous with the central hump extending axiallyoutward from the hump, and a flat shelf immediately adjacent, contiguouswith, and extending axially outward from the trough. The rim furtherincludes an integral sidewall extending generally radially outward froman intersection region of the proximal surface and the distal surface ofthe base portion of the rim. A distal point (i.e., farthest, free end)of the sidewall extends no further than 0.200 in above the shelf of thedistal surface of the rim. It will be readily appreciated that the rimconsists of two opposing sidewalls and that the distal surface of thebase portion consists of a central hump, a trough on each axial side ofthe hump, and a flat shelf extending axially from each trough out to theintersection region with the proximal surface of the base portion. In anaspect, the distal point of the sidewall extends above the shelf in therange of between about 0.150 in to 0.195 in. In another aspect, thedistal point of the sidewall extends only to between about 0.171 in to0.175 in above the shelf. These dimensional ranges present a sidewallhaving a height, hereinafter denoted by H, that is on the order of 2millimeters less than the sidewall height of a conventional bicyclewheel rim. A shorter sidewall as embodied herein not only results in areduction in the weight of the rim, it also reduces the mechanicalleverage that the tire has on the rim, making the rim stiffer andpotentially longer lasting by eliminating flexing of the rim, which canlead to cracking. This feature also eliminates the need for cornerreinforcement of the rim. Further advantages of a smaller sidewallheight include less incidents of pinch flat compared to conventionalrims, either with or without tubes, the ability to run lower airpressure in the tire based upon a larger available air volume, andapproximately 4 mm more tire surface exposure for improved traction.

According to the embodiments of the invention, the inner profile of thesidewall has substantially the same profile shape as the bead of thetire. This produces a ‘ball-and-socket’ type fit that helps to reducestrain on the tire bead while creating a tighter air seal. Theconventional bead lock at the distal end of the sidewall also has beeneliminated. Thus, in an aspect, additional material can be used in thecentral part of the proximal surface of the rim for added strength andstiffness without increasing the overall weight of the rim.

The hump in the center of the distal surface of the rim is generallyconvex-shaped, forming an arch-type structure that adds additionalstrength to the rim. Alternatively, the hump may have a generallyflat-top or other shape. The hump does not extend above the shelf of thedistal surface as this would make tire mounting difficult. The troughsextending axially away from both sides of the hump provide separatechannels for each tire bead. This feature greatly eases the effort ofinflation as the separate channels make it easier to trap air. The humpalso acts to keep the tire spread apart and allow for the valve stem toinject air directly into the center of the tire.

Another embodiment of the invention is directed to a bicycle wheel,including a rim as outlined above, a plurality of spokes engaged atrespective ends thereof with the rim, and a hub engaged with theplurality of spoke members at opposite ends thereof.

Another embodiment of the invention is directed to a bicycle wheelassembly comprising a bicycle wheel as outlined herein above, and a tubeand/or tire mounted on the rim.

The foregoing and other objects, features, and advantages of embodimentsof the present invention will be apparent from the following detaileddescription of the preferred embodiments, which makes reference toseveral drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of an exemplary bicycle wheel rim withan inflatable tire mounted thereon as known in the prior art;

FIG. 2 is a cross sectional view of a bicycle wheel rim according to anembodiment of the invention;

FIG. 3 is a figure identical to FIG. 2 with the addition of a mounted,inflated tire according to an embodiment of the invention;

FIG. 4 is a view identical to that of FIG. 2 showing dimensional indiciaaccording to an exemplary aspect of the invention;

FIG. 5 is a cross sectional view of a bicycle wheel rim according to anexemplary aspect of the invention;

FIG. 6 is a cross sectional view of a bicycle wheel rim according to anexemplary aspect of the invention;

FIG. 7 is a cross sectional view of a bicycle wheel rim according to anexemplary aspect of the invention; and

FIG. 8 is a cross sectional view of a bicycle wheel assembly accordingto an embodiment of the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Reference is now made to FIG. 2, which shows a bicycle wheel rim 500 incross sectional view according to an embodiment of the invention.According to embodiments of the invention, the rim 500 is adaptable formounting a tubeless tire shown at 600 in FIG. 3 or a tire including aninner tube 610 as illustrated in FIG. 8. As shown in FIG. 1, the rim 500has a circular base portion 505 having a proximal surface 508 that isengageable with a plurality of spokes 710 (see FIG. 8). The base portionalso has a distal surface 511 in opposition to proximal surface 508that, in part, supports the tube and/or tire. As shown in cross section,the distal surface 511 has a central hump 514, a trough 517 that iscontiguous with the central hump, and a flat shelf 520 immediatelyadjacent and contiguous with the trough. The rim further has an integralsidewall 530 that extends generally radially upward from an intersectingregion 533 of the proximal surface and the distal surface. In allembodiments set forth herein, the sidewall has a height, H, defined asthe distance between the surface of the shelf 520 and a distal point 536of the sidewall 530 that is less than or equal to 0.200 inches. FIG. 4illustrates the sidewall height, H. The maximum sidewall height, H, ison the order of 2 mm less than the corresponding height of conventionalrim sidewalls, which typically ranges between about 0.225 in to 0.265 inand above. The reduced sidewall height as embodied herein providesnumerous advantages. For example, less of the tire sidewall is availableto exert pressure against the rim sidewall; thus, there is lessmechanical leverage exerted by the tire against the rim sidewall. Thisfurther results in less flexing of the sidewall particularly in theregion designated at 533 in FIG. 2 where cracking and material fatiguemay occur. Furthermore, approximately 4 mm more tire surface isavailable resulting in a larger air volume, the ability to run lowertire pressures, increased traction and reduced incidents of pinch flator snake-bite puncture. In a particular aspect, the sidewall height, H,is between 0.150 in to 0.195 in. In an exemplary aspect, the sidewallheight is between about 0.171 in to 0.175 in.

It will be noted that the distal end 536 of the sidewall 530 does notinclude a bead lock portion. This is due, in part, to a desirable aspectof the sidewall design; that is, the interior surface profile 542 of thesidewall has a region designated at 541 where the sidewall surfaceblends to the surface of the flat shelf, that substantially correspondsto a profile shape 650 of the tire bead 620 as illustrated in FIG. 3.This correspondingly similar shape of the sidewall interior surface 541provides a “ball-and-socket” fit between the sidewall and the tire beadwhen the tire is fully inflated. The need for a bead lock is thuseliminated and as shown in the figures, the sidewall 530 does not have abulbous shape at the distal end 536, as in the prior art of FIG. 1, sothat a thickness of the sidewall 530 is not increased from where thesidewall 530 begins to extend inwardly to the distal end 536. Sinceweight reduction is always a goal of improved rim design, elimination ofthe bead lock eliminates the weight associated with them. In an aspect,illustrated in FIG. 6, the weight savings from the bead lock eliminationcan be redistributed to other regions of the rim for increased strength;for example, the central region 509 of the proximal surface of the rimcan be thickened as shown at 510 without increasing the overall weightof the rim. In an exemplary embodiment, the bead seat 520 is disposedhorizontally with respect to an axial direction of a rim. FIG. 8 showssuch a configuration.

In still another aspect relating to sidewall design, the outer surfaceof the sidewall can be squared off, for example, as shown at 539 in FIG.7.

Referring again to FIG. 2, in the illustrated aspect, the distal surface511 is smooth and continuous; i.e., it contains no acute inflectionpoints between the shelves 520, the troughs 517 or the hump 514. Asfurther illustrated, the hump has a substantially convex profile. Thisshape forms an arch structure along the center of the rim surface thatcontributes to the strength and stiffness of the rim. In an alternativeaspect as illustrated in FIG. 5, the hump may be flat topped as shown at516 or be otherwise shaped as those skilled in the art will appreciate.As shown in FIG. 4, a distal point 515 of the hump 514 extends adistance, Y, above the base of the trough 517. According to an aspect ofthe embodiment, the value, Y, is between about 0.054 in to 0.062 in. Inan exemplary aspect, Y has a value of approximately 0.058 in.

It can be further observed in FIG. 2 that the troughs 517 on oppositeaxial sides of the hump 514 effectively form two channels. When a tireis initially mounted on the rim, each of the tire beads will sit in arespective trough region 517. Not only do the hump and troughs serve tokeep the tire beads separated and confined prior to and duringinflation, the separate channels created by the troughs make it easierto trap air and thus easier to inflate the tire particularly in the caseof manual pumping. The hump and troughs also keep the tire spread apartand allow for the valve stem (not shown) to inject the air directly intothe center of the tire, easing the inflation process. In an aspect asillustrated in FIG. 4, the overall trough distance, X, (alternatively,the separation distance between the shelf portions 520) is between about0.300 in to 0.700 in. This range of separation distance, X, willaccommodate various tire profiles. In a more particular aspect, X isbetween about 0.535 in to 0.549 in. In an exemplary aspect, X isapproximately equal to 0.542 in.

According to another embodiment, illustrated with respect to FIG. 8, abicycle wheel 900 includes a rim 500 as described above in all itsvarious aspects, a plurality of spokes 710 engaged at respective ends711 thereof with the rim and a hub 800 engaged with the plurality ofspokes at opposite ends 712 thereof.

In another embodiment, a bicycle wheel assembly includes the wheel 900as schematically illustrated in FIG. 8 and further includes a tire 600mounted on the wheel rim. In an aspect, a tube 610 may be used.

The foregoing description of the preferred embodiment of the inventionhas been presented for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the above teaching. It is intended that the scope of theinvention be limited not by this detailed description, but rather by theclaims appended hereto.

1. A bicycle wheel rim, comprising: a base portion including a proximal surface having a portion engageable with a spoke member and an opposing distal surface having flat bead seats engageable with a surface of a tire; and two opposing sidewalls extending from the base portion, wherein each of the sidewalls has an inner surface profile that matches a contour of an engaging surface of the tire along the entire sidewall, further wherein the profiles respectively have an inner surface that extends inwardly and is curved at an intersection point of the flat bead seats with the two opposing sidewalls, and such that a bulbous bead lock portion is absent from a distal region of each sidewall so that a thickness of the sidewalls is not increased from where the sidewalls begin to extend inwardly to a point of each sidewall most distal the bead seats, wherein the bead seats are horizontally disposed with respect to an axial direction of the rim so that when the tire is mounted, beads of the tire are placed between the flat bead seats and the sidewalls to provide a ball and socket fit, and wherein the sidewalls extend from intersections of the proximal surface and the distal surface, and wherein the point of each of the sidewalls most distal the flat bead seats respectively extends no further than 0.200 inches above the flat bead seats of the distal surface of the rim.
 2. The rim of claim 1, wherein the sidewalls have an outer surface facing in an outward direction of the rim and the outer surface has a contour that follows the contour of the inner surface profile.
 3. The rim of claim 1, wherein the point of each of the sidewalls most distal the bead seats respectively extends from between 0.150 inches to 0.195 inches above the bead seats of the distal surface of the rim.
 4. The rim of claim 3, wherein the point of each of the sidewalls most distal the bead seats respectively extends between 0.171 inches to 0.175 inches above the bead seats of the distal surface of the rim.
 5. The rim of claim 1 wherein the distal surface of the rim has a central hump and a trough, such that the trough is contiguous with the central hump.
 6. The rim of claim 5, wherein the hump has a substantially convex cross sectional profile.
 7. The rim of claim 5, wherein the hump has a substantially arched cross sectional profile.
 8. The rim of claim 5, wherein the hump has a substantially flat-topped cross sectional profile.
 9. The rim of claim 1, wherein a central region of the proximal surface has a material thickness greater than the material thickness of a peripheral region of the proximal surface.
 10. The rim of claim 1, wherein the distal surface comprises a single hump and two troughs.
 11. The rim of claim 1, wherein the distal surface of the rim has a trough and the bead seats are immediately adjacent and contiguous with the trough to the intersection point of the bead seats with the two opposing sidewalls.
 12. The rim of claim 1, wherein the two bead seats are separated by a distance, x, where 0.300in<x<0.700 in.
 13. The rim of claim 12, wherein 0.535 in<x<0.549 in.
 14. A bicycle wheel, comprising: a plurality of spoke members engaged at respective ends thereof with a rim; and a hub engaged with the plurality of spoke members at opposite ends thereof, the rim comprising: a base portion including a proximal surface having a portion engageable with a spoke member and an opposing distal surface having flat bead seats engageable with a surface of a tire; and two opposing sidewalls extending from the base portion, wherein each of the sidewalls has an inner surface profile that matches a contour of an engaging surface of the tire along the entire sidewall, further wherein the profiles respectively have an inner surface that extends inwardly and is curved at an intersection point of the flat bead seats with the two opposing sidewalls, and such that a bulbous bead lock portion is absent from a distal region of each sidewall so that a thickness of the sidewalls is not increased from where the sidewalls begin to extend inwardly to a point of each sidewall most distal the bead seats, wherein the bead seats are horizontally disposed with respect to an axial direction of the rim so that when the tire is mounted, beads of the tire are placed between the flat bead seats and the sidewalls to provide a ball and socket fit, and wherein the sidewalls extend from intersections of the proximal surface and the distal surface, and wherein a point of each of the sidewalls most distal the flat bead seats respectively extends no further than 0.200 inches above the flat bead seats of the distal surface of the rim.
 15. The bicycle wheel of claim 14, wherein the distal surface of the rim has a trough and the bead seats are immediately adjacent and contiguous with the trough to the intersection point of the bead seats with the two opposing sidewalls. 